The present invention relates to a system for controlling an illuminating angle of a flashlight.
Such a system conventionally known is a system in which an illuminating angle of a flashlight is controlled according to a focal length of a photographing lens and the like. Since the illuminating angle is controlled by moving a illumination panel, a reflector, and the like, it is required to detect a position of the reflector and the like in order to set a desired illuminating angle. Conventionally, since the positions of the illumination panel and the like are detected by using a code board and a slice contacted therewith, there are the following shortcomings:
That is, as a result of robbing the code board and the slice together, the system is poor for durability and the improvement therefor makes it costly.
Further, it is necessary to make the code pattern sizable in order to certainly contact the code board with the slice. Furthermore, concretely speaking, the system is constructed in such a manner that the motor is stopped when the slice contacts with the code pattern. It is found in such construction that even if the motor is braked, it still more rotates by the force of inertia, thereby the slice passing over the code pattern. When the slice passes over the code pattern, means for controlling the position of the panel and the like drives the motor so as to move the panel and the like in the reverse direction. Similarly when the slice passes over the code pattern, the same operations as the abovementioned are repeated, with the result that the panel and the like are moved back and forth. For the purpose of preventing this annoying moving, it is necessary to make the code pattern sizable as described above.
On the other hand, making the code pattern larger causes the system itself to be enlarged and moreover, not making it larger causes to decrease the number of detecting points. When the number thereof is a few, the precise control is not able to be performed and thus waste light results in illuminating an object. For example, if the detecting points are 35 mm, 50 mm, and 70 mm in the focal length of the photographing lens, in case of employing the photographing lens of the focal length 40 mm, the illuminating angle must cover the view angle of the lens with the focal length 35 mm (it is wider than the view angle of the lens with the focal length 40 mm) and thus, the unnecessary light which is not used to photograph an object results in illuminating.
Furthermore, when the system is constructed in such a manner that the positions of the illumination panel and the like is detected by using the code board and the slice, it is necessary to provide many members including the code board, the slice, the members for supporting them, the lead wires connected to the code board, and the like, thereby the number of parts also increasing.